Gas filled measuring condenser

ABSTRACT

A condenser, especially for measurement purposes, in which the high voltage electrode and the low voltage electrode are arranged on the inside of an insulating casing housing filled with a gas; the space between the high voltage electrode and the low voltage electrode or a space enclosed by an auxiliary electrode surrounding the high voltage and low voltage electrodes is closed off insulatingly gas-tight and the pressure of the gas in this space is higher than the pressure of the gas in the space formed between such electrodes and the insulating casing housing.

United States Patent 1191 Raupach [4 1 Aug. 13, 1974 [76] inventor!Friedrich Raupach, Wildensorget 933,351 9/1955 Germany 317/244 Strasse9, Bamberg, Germany 22 Filed; Man 23 1973 Primary ExaminerE. A. GoldbergAttorney, Agent, or Firm-Craig & Antonelli [21] Appl. No.: 344,146

[57] ABSTRACT [30] Foreign Application Priority Data A condenser,especially for measurement purposes, in Mar. 24, 1972 Germany 2214288which g Voltage electrode and the low voltage electrode are arranged onthe inside of an insulating 52 us. 01 317/244, 317/242, 317/246 Casinghousing filled with a gas; the Space between the 511 1m. 01 HOlg 5/02high voltage electrode and the low voltage electrode [58] Field ofSearch 317/242, 245, 244, 246 Or a Space enclosed y an auxiliaryelectrode rounding the high voltage and low voltage electrodes 5References Cited is closed off insulatingly gas-tight and the pressureof UNITED STATES PATENTS the gas in this space is higher than thepressure of the 2 900 585 H K H 317/244 gas in the space formed betweensuch electrodes and e Cl 3,242,397 3/1966 Jennings 317/245 the msulatmgcasmg housmg' 3,405,559 10/1968 Moffatt 317/246 x 34 Claims, 2 DrawingFigures II I PATENIEU Am 1 31914 9,7

sum 2 or 2 FIG 2 GAS FILLED MEASURING CONDENSER The present inventionrelates to a condenser, and in particular to a condenser used formeasuring purposes in which the high voltage electrode and the lowvoltage electrode are arranged on the inside of an insulating casingfilled with a gas.

With the frequently used pressure gas condensers according toSchering-Vieweg for high and very high voltages, as are required formeasurements, especially for loss factor measurements, instrumenttransformer calibrations, etc., the high voltage electrode and the lowvoltage electrode consist of metallic cylinders coaxially surroundingone another which are accommodated in an insulating tube or pipe filledwith pressure gas, i.e., with a compressed gas. As a rule, the highvoltage electrode is secured at the metallic cover of the insulatingtube which is at the high voltage potential whereas the cylindrical lowvoltage electrode surrounded by the high voltage electrode is carried bya column secured on the grounded floor plate of the insulating tube.

These prior art compressed gas condensers distinguish themselves by alow loss factor and by a practically non-measurable independence fromexternal or foreign fields. However, the external insulation offersdifficulties since the field is not controlled by intermediateelectrodes but instead the potential is reduced in a single stage.Furthermore, a coaxial cylindrical field is more unfavorableelectrostatically than, for example, a field which forms betweenapproximately flat electrodes. For achieving a high dielectric strength,it is therefore necessary to improve the insulating properties of thepressure gas which has been achieved with the heretofore customaryconstructions by the use of a high pressure in the pressure gascontainer approximately at a magnitude of 14 atm. (atmosphere gauge)(Keller: Konstanz der Kapazitaet von Pressgaskondensatoren, ETZ-A Volume80, 1959, pages 757-761). J

To avoid these difficulties, a high voltage condenser for measuringpurposes has been disclosed which is characterized in that the twopreferably spherically shaped or semi-spherically electrodes thereof arearranged one above the other in the axial direction of the insulatingtube on the inside of an essentially cylindrical intermediate electrodewhich is secured approximately at half the height in the insulating tubeand is held at a potential lying between the potential of the highvoltage electrode and the low voltage electrode (GermanOffenlegungsschrift 1,514,203).

With such a condenser, the external insulation problem becomesconsiderably more simple because the voltage is reduced at two places ofthe insulating tube. With the same insulating tube diameter and the samepermissive surface field strength, one can therefore controlapproximately twice the voltage than with the pressure gas condensersaccording to Schering-Vieweg as mentioned hereinabove. It is also ofadvantage that the gas pressure in the pressure gas container can bekept lower than necessary heretofore. With the use of sulfurhexafluorideone is able to get along even with a pressure of 2-3 atm. (atmosphericexcess pressure). While one does not obtain a'complete independence fromexternal fields as with the condensers having mutually coaxial high andlow voltage electrodes, the external field influence nonetheless is soslight that it does not disturb or cause any problems.

The present invention relates to a condenser, especially for measurementpurposes, in which the high voltage electrode and the low voltageelectrode are arranged on the inside of an insulating casing housingfilled with gas.

The present invention is concerned with the task to so construct such acondenser that it excels by a slight requirement in insulating gas, ahigh operational reliability and safety and small dimensions.

The underlying problems are solved according to one embodiment of thepresent invention in that the space between the high voltage electrodeand of the low voltage electrode is closed off insulatingly gas-tightand that the pressure of the gas in the space formed by the high voltageelectrode and the low voltage electrode is higher than the pressure ofthe gas in the space between the electrodes and the insulating casinghousing.

By the subdivision of the condenser into a measurement condenser spacedformed by the high voltage electrode and the low voltage electrode andinto a leadin space disposed outside of the electrodes and delimited bythe insulating casing housing, whereby exclusively the measuringcondenser space is provided with the higher gas pressure required forthe rated voltage whereas the lead-in space has a considerably lower gaspressure, one achieves a considerable saving in insulating gas. The gaspressure can be selected relatively high in the comparatively smallmeasurement condenser space. As a result thereof, the radial distancebetween the electrodes, on the one hand, and between the electrodes andthe insulating casing housing, on the other, can be reduced becausedielectric strength increases with the pressure of the insulating gas,which enables a slender design and small construction. The over-allinsulating gas expenditure is relatively small compared with the knowncondensers of this type because the gas pressure in the lead-in spacewhich has a considerably larger volume than the measurement condenserspace, can be relatively low. The pressure may preferably amount toabout 1 ata in the lead-in space.

The subdivision of the condenser space according to the presentinvention into a measurement condenser space with higher gas pressureand into a lead-through space with lower gas pressure is applicable withadvantage not only to condensers which are designed according to theconstructional principle of Schering-Vieweg, i.e., with mutually coaxialhigh voltage and low voltage electrodes but with the same or similaradvantages also to condensers having electrodes arranged axially oneabove the other and an auxiliary electrode according to Kind.

The present invention according to a further embodiment therefore alsorelates to a condenser, especially for measurement purposes, in whichthe high voltage electrode and the low voltage electrode are surroundedfar-reachingly by an auxiliary electrode which is at approximately halfthe high voltage potential whereby the auxiliary electrode is arrangedeither completely or partially on the inside of an insulating casinghousing filled with a gas. According to the present invention, the spacebetween the high voltage electrode and the auxiliary electrode, on theone hand, and between the low voltage electrode and the auxiliaryelectrode, on the other, is closed off insulatingly gas-tight wherebythe pressure of the gas in the space constituted by the high voltageelectrode, the low voltage electrode and the auxiliary electrode ishigher than the pressure of the gas in the space or spaces between theelectrodes and the insulating casing housing. In addition to theadvantages described above, the further advantage is achieved therebythat the axial distance between the high voltage electrode and the lowvoltage electrode can be reduced whence the capacity of the condenser isincreased which is frequently desirable.

Accordingly, it is an object of the present invention to provide acondenser, especially for measurement purposes which avoids byv simplemeans the aforementioned shortcomings and drawbacks encountered in theprior art.

Another object of the present invention resides in a condenser of thetype described above in which the external insulation problem isconsiderably simplified while at the same time a significant saving ininsulating gas is realized.

A still further object of the present invention resides in a pressuregas condenser which is extraordinarily reliable in operation anddistinguishes itself by small dimensions.

Another object of the present invention resides in a condenser of thetype described above in which the capacity of the condenser can beincreased.

These and further objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing which shows, forpurposes of illustration only, two embodiments in accordance with thepresent invention, and wherein:

FIG. 1 is a longitudinal cross-sectional view through a condenser inaccordance with the present invention with high voltage and low voltageelectrodes arranged coaxially to one another; and I FIG. 2 is alongitudinal cross-sectional view through a condenser according to thepresent invention with high voltage and low voltage electrodes arrangedone above the other in the axial direction of the insulating casing aswell as with an auxiliary electrode surrounding the same.

Referring now to the drawing, and more particularly to H0. 1, thecondenser illustrated in this figure, preferably a pressure gascondenser for high and very high voltages, includes an insulating casing1 consisting of casting resin or any other suitable insulating materialas known in the art, which is closed off at the top by a metallic cover2 having a shielding hood 3 and at the bottom by a metal bottom 4. A lowvoltage electrode 5 is completely shielded by a high voltage electrode 6surrounding the same. The high voltage electrode 6 is extendeddownwardly relatively far and terminates in a bulged or beaded ring 7that has such a small distance from a grounded tubular member 8 carryingthe low voltage electrode 5 that no external field lines can penetrateonto the measurement layer. A feed line leading to the measurementelectrode (low voltage electrode) 5 is designated by reference numeral 9which is disposed within the grounded support pipe 8. A support ring 10is secured at the high voltage electrode 6; one

7 end of a conical-disk-shaped supporting-type insulator The spaceclosed off gas-tight by the supporting-type bushing 11 between the lowvoltage electrode 5 and the highvoltage electrode 6 is filled with aninert gas, for example, nitrogen or with an electro-negative gas,preferably sulfur hexafluoride having a higher pressure. The gaspressure P of the insulating gas in the measurement condenser spaceformed by the electrodes 5 and 6 may preferably be within the rangebetween about i and 10 atm.,, The gas pressure P in the lead-in spacedisposed on the outside of the electrodes 5 and 6 may amount preferablyto about 1 ata. Also, the leadin space is filled preferably with aninert or electronegative gas, preferably sulfur hexafluoride. As aresult of the subdivision of the condenser according to the presentinvention into the two pressure spaces, the expenditure in insulatinggas is considerably reduced compared to the known constructions. Sincethe electrode distances can be kept small in the measurementcondenserspace, one additionally obtains a very compact, slender type ofconstruction.

The condenser illustrated in FIG. 2 includes also an insulating casing21 which is closed off at the top by a metal cover 22 with a shieldinghood 23 and at the bottom by a metal bottom 24. Approximately at halfthe height of the insulating casing 21 are located the electrodes 25 and26 disposed one above the other in the direction of the casing axis and,for example, provided with a Rogowski-profile or plate-shaped. The highvoltage electrode 25 is secured at the cover 22 by means of a pipe ortubular member 27 whereas the low voltage electrode 26 is carried by apipe or tubular member 28 secured at the bottom 24. The high voltage andlow voltage electrodes 25 and 26 are surrounded by an auxiliaryelectrode 29 closed off in a gas-tight manner and filled with aninsulating gas of higher pressure. The auxiliary electrode 29 arrangedon the inside of the insulating casing 21 consists of two approximatelysemispherically shaped shells 30 and 31 which are provided each with anaperture 32 and 33 for the tubular support members or pipes 27 and 28 ofthe electrodes 25 and 26, respectively. The apertures 32 and 33 of thehousing shells 30 and 31 are closed off gas-tight by coneshapedsupporting-type insulator bushings 34 and 35 tapering in the upward anddownward direction respectively and preferably consisting of castingresin of any suitable known type. Support rings 36 and 37 consistingpreferably of insulating casting resin and secured at the housing shells30 and 31 are provided as abutment surfaces for the conically shapedsupporting-type bushings 34 and 35. The insulating casing 21 issubdivided into two insulating casing portions 38 and 39 which areprovided with recesses 41 and 42 at the separating place 40, in whichare guided flange rings 43 and 44 secured at the outwardly bent edge ofthe housing shells 30 and 31 and are threadably secured with theinsulating casing portions 38 and 39 by means of screws or bolts 45 and46 distributed over the circumference. The insulating casing portions 38and 39 are connected with each other in a gas-tight manner by sealingrings (not shown) with the use of bolts or screws 49 mounted at theprojections 47 and 48. The separating place 40 is surrounded by anannular screening electrode 50. The tubular support members 27 and 28consist each of two portions 51, 52 and 53, 54 whereby the separatingplaces 55 and 56 are provided in proximity of the tapering ends of theconically shaped supporting-type bushings 34 and 35. Threaded pins 57and 58 secured at the end of the shorter partial tubular members 52 and54 disposed on the inside of the auxiliary electrode 29 serve asconnecting means of the tubular support portions 51, 52 and 53, 54. As aresult thereof, temperature-conditioned changes in length of the tubularsupport members 27 and 28 have no influence on the main capacity of thecondenser conditioned by the electrodes 25 and 26 with differentcoefficients of expansion between the tubular support members 27, 28 andthe insulating casing 21. Thus, a matching of the coefficients ofexpansion which is possible as such, of the tubular support members 27and 28 to the insulating casing 21 can therefore be dispensed with. Theauxiliary electrode 29 is filled with an electro-negative gas,preferably sulfur hexafiuoride. The pressure of the insulating gas liespreferably again withinthe range of between about 1 and atm. Also. thespace(lead-in space) located on the outside of the auxiliary electrode29 and surrounded by the insulating casing 21 can be filled with anelectro-negative gas, however, having a lower pressure, for example,about I ata. Also mixtures of electro-negative gases with other inertgases can be used both in the measurement condenser space as also in thelead-in space. A relatively high pressure on the inside of themeasurement condenser space makes it possible that with a predeterminedrated voltage, the electrode surfaces F can be increased and theelectrode spacing A can be decreased, which brings about a highercapacity as is desirable for various measurements. On the other hand,with an unchanged electrode surface F and electrode spacing A, and witha higher insulating gas pressure in the auxiliary electrode 29, thecondenser could be loaded with a higher voltage. An increase of thepressure P, on the inside of the auxiliary electrode 29 requires as arule no increase of the pressure P of the space surrounded by theinsulating casing 21 on the outside of the auxiliary electrode 29.Instead, a gas pressure P of preferably about 1 ata suffices even withhigh up to very high voltages in the lead-in space if also this pressurespace is filled with an inert, preferably electro-negative gas.

The auxiliary electrode 29 need not necessarily be located completely onthe inside of the insulating casing 21. For example, the insulatingcasing portions 38 and 39 could also be secured at the support rings 36and 37 whereby the diameter of the insulating casing portions 38 and 39would be considerably reduced. The electrodes 25 and 26 may also have ashape different from that shown on the drawing, for example, the shapeof a ball, of a mushroom or of an elipsoid. Instead of cone-disk-shapedsupporting-type bushings, also disk-shaped or funnel-shaped supportingtype bushings can be used.

A further significant advantage of the present invention resides in thatboth in the embodiment according to FIG. 1 as also in the embodimentaccording to FIG. 2, the gas pressure in the space constituted by thehigh voltage electrode and the low voltage electrode or/and theauxiliary electrode and the gas pressure in the space or spaces betweenthese electrodes and the insulating casing housing can be so adjusted ineach case that the product of gas volumes and gas pressure in bothpressure spaces is so selected that the condenser can be shipped in theready-to-use condition (with gas filling) taking into consideration theapplicable safety rules and requirements. As a result thereof,condensers, preferably pressure gas condensers up to the highestoccurring voltage planes can be shipped ready for use wherebyconsiderable costs can be saved for the discharge and refilling of theinsulating gas as well as for the preparation thereof at the location ofuse of the condenser.

While I have shown and described two embodiments in accordance with thepresent invention, it is understood that the same is not limited theretobut is susceptible of numerous changes and modifications as known tothose skilled in the art, and I therefore do not wish to be limited tothe details shown and described herein but intend to cover all suchchanges and modifications as are encompassed by the scope of theappended claims.

What I claim is:

l. A condenser, especially for measurement purposes, comprising aninsulating casing housing means, electrode means including a highvoltage electrode means and a low voltage electrode means arranged onthe inside of said insulating casing housing means filled with a gas,characterized in that a first space is formed between the high voltageelectrode means and the low voltage electrode means and is closed offinsulating gas-tight, and in that the pressure of the gas in said firstspace which does not extend beyond the electrode means is higher thanthe pressure of the gas in a second gas-tight space formed between saidhigh voltage electrode means and the insulating casing housing means.

2. A condenser, especially for measurement purposes, comprising aninsulating casing housing means, electrode means including a highvoltage electrode means, a low voltage electrode means and an auxiliaryelectrode means arranged on the inside of said insulating casing housingmeans filled with a gas, characterized in that a first space isdelimited between said high voltage and low voltage electrode means, onthe one hand, and said auxiliary electrode means, on the other and isclosed off insulating gas-tight, and in that the pressure of the gas insaid first space is higher than the pressure of the gas in a secondgas-tight space formed between said auxiliary electrode means and saidinsulating casing housing means.

3. A condenser according to claim 1, characterized in that onesupporting-type bushing means is provided as closure for the firstspace.

4. A condenser according to claim 3, characterized in that said bushingmeans is of a disk-shape.

5. A condenser according to claim 3, characterized in that said bushingmeans is of cone-disk shape.

6. A condenser according to claim 3, characterized in that said bushingmeans is funnel shaped.

7. A condenser according to claim 1, characterized in that the firstspace is filled with an inert gas.

8. A condenser according to claim 7, characterized in that said inertgas is nitrogen.

9. A condenser according to claim 1, characterized in that the firstspace is filled with an electro-negative gas in that saidelectro-negative gas is sulfur hexafluoride.

11. A condenser according to claim 1, characterized in that the highvoltage and low voltage electrode means are constructed as electrodesdisposed coaxial to one another.

10. A condenser according to claim 9, characterized 12. A condenseraccording to claim 1, characterized in that the gas pressure in thefirst space amounts to about 1 to about 10 atm.,.

13. A condenser according to claim 1, characterized in that the gaspressure in the first space and in the second space is so adjusted thatthe product of gas volumes and gas pressure in both pressure spaces isso selected that the condenser can be shipped in the readyto-useconditiontaking into consideration the applicable safety regulations.

14. A condenser according to claim 13, character ized in that the spaceis the first space enclosed by the high voltage electrode means and thelow voltage electrode means.

15. A condenser according to claim 13, characterized in that at leastone lead-in insulator is provided as closure for the first space.

16. A condenser according to claim 15, characterized in that the spaceis the first space enclosed by the high voltage electrode means and thelow voltage electrode means.

17. A condenser, especially for measurement purposes, in which a highvoltage electrode means and a low voltage electrode means are surroundedat least far-reachingly by an auxiliary electrode means which is atapproximately half the high voltage potential, and in which theauxiliary electrode means is arranged at least partially on the insideof an insulating casing housing means filled with a gas, characterizedin that the space between the high voltage electrode means and the lowvoltage electrode means, on the one hand, and between the low voltageelectrode means and the auxiliary electrode means, on the other, isclosed insulatingly gastight, and in that the pressure of the gas in thespace constituted by the high voltage electrode means, the low voltageelectrode means, and the auxiliary electrode means is higher than thepressure of the gas in the space between said electrode means and theinsulating casing housing means.

18. A condenser according to claim 17, characterized in that theauxiliary electrode means is arranged completely on the inside of theinsulating casing housing means filled with a gas.

19. A condenser according to claim 17, characterized in that the highvoltage electrode means and the low voltage electrode means areconstructed as electrodes disposed one above the other in the axialdirection of the insulating casing housing means.

20. A condenser according to claim 17, characterized in that saidelectrodes have relatively large radii of curvature on the sides facingone another.

21. A condenser according to claim 17, characterized in that saidelectrodes are plate-shaped.

22. A condenser according to claim 17, characterized in that twosupporting-type bushing means are provided as closure for the firstspace.

23. A condenser according to claim 22, characterized in that saidbushing means is of disk-shape.

24. A condenser according to claim 22, characterized in that saidbushing means is of cone-disk shape.

25. A condenser according to claim 22, characterized in that saidbushing means is funnel shaped.

26.A condenser according to claim 17, characterized in that the firstspace is filled with an inert gas.

27. A condenser according to claim 26, characterized in that said inertgas is nitrogen.

28. A condenser according to claim 17, characterized in that the firstspace is filled with an electronegative gas.

29. A condenser according to claim 28, characterized in that saidelectro-negative gas is sulfer hexafluoride.

30. A condenser according to claim 17, characterized in that the gaspressure in the first space amounts to about 1 to about 10 ata.

31. A condenser according to claim 17, characterized in that the gaspressure in the first space and in the second space is so adjusted thatthe product of gas volumes and gas pressure in both pressure spaces isso se lected that the condenser can be shipped in the readyto-usecondition taking into consideration the applicable safety regulations.

32. A condenser according to claim 31, characterized in that severallead-in insulators are provided as closure for the first space.

33. A condenser according to claim 31, character! ized in that the firstspace is enclosed by said auxiliary electrode means.

34. A condenser according to claim 32, characterized in that the firstspace is enclosed by said auxiliary electrode means.

1. A condenser, especially for measurement purposes, comprising aninsulating casing housing means, electrode means including a highvoltage electrode means and a low voltage electrode means arranged onthe inside of said insulating casing housing means filled with a gas,characterized in that a first space is formed between the high voltageelectrode means and the low voltage electrode means and is closed offinsulating gas-tight, and in that the pressure of the gas in said firstspace which does not extend beyond the electrode means is higher thanthe pressure of the gas in a second gas-tight space formed between saidhigh voltage electrode means and the insulating casing housing means. 2.A condenser, especially for measurement purposes, comprising aninsulating casing housing means, electrode means including a highvoltage electrode means, a low voltage electrode means and an auxiliaryelectrode means arranged on the inside of said insulating casing housingmeans filled with a gas, characterized in that a first space isdelimited between said high voltage and low voltage electrode means, onthe one hand, and said auxiliary electrode means, on the other and isclosed off insulating gas-tight, and in that the pressure of the gas insaid first space is higher than the pressure of the gas in a secondgas-tight space formed between said auxiliary electrode means and saidinsulating casing housing means.
 3. A condenser according to claim 1,characterized in that one supporting-type bushing means is provided asclosure for the first space.
 4. A condenser according to claim 3,characterized in that said bushing means is of a disk-shape.
 5. Acondenser according to claim 3, characterized in that said bushing meansis of cone-disk shape.
 6. A condenser according to claim 3,characterized in that said bushing means is funnel shaped.
 7. Acondenser according to claim 1, characterized in that the first space isfilled with an inert gas.
 8. A condenser according to claim 7,characterized in that said inert gas is nitrogen.
 9. A condenseraccording to claim 1, characterized in that the first space is filledwith an electro-negative gas.
 10. A condenser according to claim 9,characterized in that said electro-negative gas is sulfur hexafluoride.11. A condenser according to claim 1, characterized in that the highvoltage and low voltage electrode means are constructed as electrodesdisposed coaxial to one another.
 12. A condenser according to claim 1,characterized in that the gas pressure in the first space amounts toabout 1 to about 10 ata.
 13. A condenser according to claim 1,characterized in that the gas pressure in the first space and in thesecond space is so adjusted that the product of gas volumes and gaspressure in both pressure spaces is so selected that the condenser canbe shipped in the ready-to-use condition taking into consideration theapplicable safety regulations.
 14. A condenser according to claim 13,characterized in that the space is the first space enclosed by the highvoltage electrode means and the low voltage electrode means.
 15. Acondenser according to claim 13, characterized in that at least onelead-in insulator is provided as closure for the first space.
 16. Acondenser according to claim 15, characterized in that the space is thefirst space enclosed by the high voltage electrode means and the lowvoltage electrode means.
 17. A condenser, especially for measurementpurposes, in which a high voltage electrode means and a low voltageelectrode means are surrounded at least far-reachingly by an auxiliaryelectrode means which is at approximately half the high voltagepotential, and in which the auxiliary electrode means is arranged atleast partially on the inside of an insulating casing housing meansfilled with a gas, characterized in that the space between the highvoltage electrode means and the low voltage electrode means, on the onehand, and between the low voltage electrode means and the auxiliaryelectrode means, on the other, is closed insulatingly gas-tight, and inthat the pressure of the gas in the space constituted by the highvoltage electrode means, the low voltage electrode means, and theauxiliary electrode means is higher than the pressure of the gas in thespace between said electrode means and the insulating casing housingmeans.
 18. A condenser according to claim 17, characterized in that theauxiliary electrode means is arranged completely on the inside of theinsulating casing housing means filled with a gas.
 19. A condenseraccording to claim 17, characterized in that the high voltage electrodemeans and the low voltage electrode means are constructed as electrodesdisposed one above the other in the axial direction of the insulatingcasing housing means.
 20. A condenser according to claim 17,characterized in that said electrodes have relatively large radii ofcurvature on the sides facing one another.
 21. A condenser according toclaim 17, characterized in that said electrodes are plate-shaped.
 22. Acondenser according to claim 17, characterized in that twosupporting-type bushing means are provided as closure for the firstspace.
 23. A condenser according to claim 22, characterized in that saidbushing means is of disk-shape.
 24. A condenser according to claim 22,characterized in that said bushing means is of cone-disk shape.
 25. Acondenser according to claim 22, characterized in that said bushingmeans is funnel shaped.
 26. A condenser according to claim 17,characterized in that the first space is filled with an inert gas.
 27. Acondenser according to claim 26, characterized in that said inert gas isnitrogen.
 28. A condenser according to claim 17, characterized in thatthe first space is filled with an electro-negative gas.
 29. A condenseraccording to claim 28, characterized in that said electro-negative gasis sulfer hexafluoride.
 30. A condenser according to claim 17,characterized in that the gas pressure in the first space amounts toabout 1 to about 10 ata.
 31. A condenser according to claim 17,characterized in that the gas pressure in the first space and in thesecond space is so adjusted that the product of gas volumes and gaspressure in both pressure spaces is so selected that the condenser canbe shipped in the ready-to-use condition taking into consideration theapplicable safety regulations.
 32. A condenser according to claim 31,characterized in that several lead-in insulators are provided as closurefor the first space.
 33. A condenser according to claim 31,characterized in that the first space is enclosed by said auxiliaryelectrode means.
 34. A condenser according to claim 32, characterized inthat the first space is enclosed by said auxiliary electrode means.